Wifi Manager 4

After discoverig Network Stumbler, I find another indispensable WLAN network management tool, Managengine Wifi Manager 4. It can be used to monitor WLAN status, troubleshoot problems, and identify bottlenecks.

The free version can support 3 APs and 10 network devices, quite sufficient for me to use in home WLAN environment.

Wifi World record - coverage up to 129 miles

Accoridng to www.wifiworldrecord.com, with the aid of a 10-ft dish antenna at both ends, the maximum distance Wifi can achieve is 129 miles without the use of amplifier.

The connection at 11 Mbps was attained and kept up for 3 hours. During this time 11,000 successful pings were made. Both ends of the link were using SSH and logged into the other end. VNC was also used successfully WITHOUT frames being dropped. Ping times varied from 0.01 ms to 400 ms, seeming to average around 10 ms. The connection had an astounding signal strength of -37 dBm, bottoming out at around -50 dBm throughout the 3 hours. The noise levels were around -84 dBm.

iTune phone

iTune is the software for transferring songs from Windows/Mac PCs to ipod players where the audio is stored as the AAC (Apple Advanced Coding) format. I have used mp3 players and ipod and I think ipod players offer a much better sound quality. While some mobile phones already have mp3 players built-in, ipod lovers are waiting eagerly for the release of iTune phone. Finally time has come for Motorola to release the Motorola E790 iTune which can be used as an ipod player.

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Netgear RangeMax WPN824 AP

This wireless router, Model Netgear RangeMax WPN824, has recently attracted a great deal of attention in computer malls. The vendor claims that the coverage is 10 times better than 802.11b/g with the use of 7 built-in smart antennas and MIMO architecture. At any time, it will select the antenna which beams the best signal strength to reach the wireless clients.

I can not imagine how this tiny box with a book-size can have up to 7 antennas inside. I guess in the not too distant future, we will soon witness the birth of 10-antenna or 12-antenna wireless routers if more antennas can really improve the performance.

Blogger for Word

Google has developed an add-in to publish blog through Mircosoft Word. After the successful installation, a Blogger toolbar will be added.

Thats sound as an astonishing news to the blogger community. Unfortunately, images and tables appear on Word documents can not be published.

Hey…. Google needs to put more effort to overcome these obstacles.

gwbasic and qbasic

I still need to use basic to do some trivial tasks like generating large amount of HKID numbers for test purpose and intermodulations on frequency channels. Right now, with DOS shell in Windows XP, I can still run basic programs quick and smooth. I can't imagine if I can still do the same in the next version of Windows Vista as people say DOS shell will be removed in the next release.

The world's largest Wifi city

By next year, San Francisco will be the world's largest Wifi city. Free wireless Internet access will be free or at least affordable to citizens all over the 49-square mile areas via the municipal wireless network. The project is estimated to cost 18 million.

The prime objective is to bridge the digital divide which makes lower income people not able to access the Internet. All corporate employees, federal officers, police and fire departments are able to benefit.

Who will be the biggest winners ? My idea that with such a fanatastic wireless infrasturcture being put in place, the sales of notebook PCs will double or triple in San Francisco. Notebook vendors should be asked to sponsor this municpial project.

Who will be the losers ? I can imagine that 2.5G mobile operators will lose a large part of their revenues.

Will such development be extended to Hong Kong. When affordable Wifi hotspots are all over the city, I do not need to subscribe to 2.5 G or perhaps 3G service.

warchalking

These three terms starting with "war" are interesting :

Wardriving - the practice of driving around to detect open Wifi nodes.

Warchalking - the drawing of symbols in public places to advertise an open Wi-Fi wireless network that other people can use to hook up to the Internet.

Wardialing - the practice of dialing many numbers for finding a modem connection.

Certainly, wardialing has almost disappeared nowadays.

For warchalking, a special symbol is to be drawn on a nearby object, such as a wall, the pavement, or a lamp post.


In our office, we have Wifi for visitors to hook up their notebook PCs. Hmmm.... just thinking shall we warchalk the symbol on easily seen locations.

Network Stumbler

I find NetStumbler from www.netstumbler.com. This is an amazing tool for trobleshooting problems in WLAN. It can be used to find locations with poor coverage by reading the S/N ratio and whether other networks nearby might cause interference to your own WLAN. On wireless bridge application, it can help to align the directional antenna in order to get the maximum signal strength.

客機上發短訊

在希臘空難事件後 ，一男子聲稱收到機上一名乘客的手機短訊，指就快凍死。最後該名男子被控以散播虛假資料及引起公眾騷亂罪名。

其實這宗大話很容易被識破，流動電話網絡採用的板面天線向地面傾側，主要集中覆蓋地面。客機在逾萬呎高空飛行，根本沒可能接收到流動電話網絡訊號。

Virtual Server via NAT

My wirless broadband router, model Planet BLW-04EM can support Virtual Server. That is to say, the WAN interface can pass Internet traffic to an internal host 192.168.1.x as if the services residing in 192.168.1.X are on the Internet. I have started IIS and access the WAN real IP address can redirect to my default web page through the internal network. That is to say, the Virtual Server is up and working satisfcatorily. However, if I try to access http:// followed by the WAN IP address from other hosts on the Internet, nothing can be seen. I believe my ISP has barred inbound traffic to port 80 of client IP addresses. Just wonder what good it is to ban port 80 inbound traffic ....

Running Windows and Linux on PSP

Great news to PSP lovers. By using Bochs x86 emulator, Windows and Linux can be ported to PSP. The Bochs packages now include FreeDOS, Linux, DLX Linux, NetBSD, OpenBSD and Windows.

I don't quite understand how these things work !

tcping

Tcping is an alternative to icmp ping as nowadays most network administrators have banned inbound icmp traffic to their Internet hosts for security reason. Tcping does not use icmp, rather it uses tcp sync, ack and nop (no operation) to complete the two way connection sequences. It could be used to determine the round trip time to a host and also testing whether a host is live or not.

Tcping requires a port number in addition to the destination IP address when initiating the command.

Tcping in Linux can be found everywhere on the Internet. It is difficult to find Windows-based tcping. Fortunately, I've got one.

Reborn card

Game centers, Internet cafes and universities all have reborn cards installed in PCs.

Reborn-card will wipe out any installed programs by users at bootup and return to the Day 1 installed configuration. Good for preventing viruses and malicious codes and to ensure all the default configurations are not changed in any way.

For universities, people think that there might be a need to set aside a special partition to store user data where the data will remain intact upon bootup. Hey....man, I rather think that with the emergence of USB memory finger at extremely low cost, it is redundant to consider such a common partition.

USB DECT VoIP Phone

Linksys Model CIT200 is really a fantastic VoIP DECT phone. The phone itself is running skype VoIP and the base unit is connected back to a PC via USB for hooking up to the Internet. The colour display defintely attracts a great deal of attention.

It seems that PSTN DECT phones are being phased out now.

This phone is not available in Hong Kong yet. We may have to wait for several months for this product to come to our place.

Affordable 10GB Network Storage Service

I've got an offer of 10GB network ftp storage from Visicom Media at US$5.95 per month. The login process and file transfer are enhanced with encryption for security reason.

I think not only personal users need the backup storage, cooporate users also need the backup service to protect against the danger of fire in offices. Thought it is affordable to me, I very much hope HK ISP can provide this kind of service. After all, sending 100 MB of encrypted data to an US storage server consume considerable time due to limitation in international bandwidth of my ISP.

Wooo.. finally, the day has come for service providers to roll-out affordable network storage service. Many people have dream about this for a long time.

new gTLDs

The following seven additional gTLDs have been approved by ICANN in November 2000 and are now open for registration:

.aero - for the air transport industry
.biz - for business use, an alternative to .com
.coop - for cooperatives
.info - for informational sites, but unrestricted
.name - for individuals
.museum - of course for museum
.pro - for professionals

The ".name" and ".pro" domains sound not attractive to me. I would prefer to have my personal domain names ending with ".com" or ".idv.hk" or just ".hk".

cygwin

cygwin

Top 10 Most Wanted Offenders

Dshield.org has published the most wanted 10 offenders which are engaged in cracking activities.



The IP address 60.18.168.25 is logged in 1632859 lines of firewall logs/reports submitted by different parties and it is estimated that up to 223286 hosts have been targetted for attack. This IP address 60.18.168.25 is originating from mainland China. Fighting back initiative has been launched by Dshield to ask the corresponding ISP or service provider to take appropriate actions.

chroot environment for name daemon

In Fedora Core series, the DNS daemon "named" is run in a chroot environment. The default directory path is changed to "/var/named/chroot/var/named" instead of "/var/named".

The idea behind chroot is to tighten security. The service is also run by a non-root user. In a chroot jail, the process is unable to access any files outside the jail. This process prevents malicious code to start in the even of buffer overflow.

Congratulations to Redhat Fedora Core team for successfully improving security of DNS service.